This invention relates generally to the field of electromagnetic therapeutics. More particularly, the invention is directed to the generation and use of electromagnetic fields in interaction with a biological body to effect internal warming of the body in the treatment of severe hypothermia.
Hypothermia often results from prolonged exposure to cold under adverse conditions such as by immersion of personnel in water following boating accidents, downed aircraft, or the like. Once the "core" temperature of a person has fallen significantly below normal and a condition of severe hypothermia exists, that condition is not easily reversed and death often follows. Active central rewarming of the body is needed as quickly as possible and peritoneal dialysis by warming fluids has been the treatment of choice for severe hypothermia. However, since that is an invasive technique requiring substantial clinical support, peritoneal dialysis cannot be accomplished in remote field locations or aboard ships with limited medical facilities. Breathing warm, humidified air provides some deep body core heating, and there are devices commercially available for that purpose. Inhalation warming methods, however, are relatively slow and are best suited to treatment of mild hypothermia. Warm water immersion treatment is ineffective as there is a high risk that the rest of the body will warm up faster than the heart, which quickly leads to cardiac arrest.
A variety of devices and techniques are known for therapeutic treatment of cancers or other tumors by hyperthermia, i.e., unnaturally elevated body temperature, induced by electromagnetic wave energy at radio wave or microwave frequencies. These, again, have been limited to clinical settings, generally involve non-portable equipment, and require highly trained medical and technical personnel operating under carefully controlled conditions to avoid or minimize injury to healthy tissues because of the abnormally high temperatures involved. The various apparatus used in inducing such temperatures generally attempt to concentrate or focus energy on or at a localized tumer site. Because of that concentration, and because the SAR (specific absorption rate) of energy at the body surface is much more than that at the central portions of a subject's body, use of known hyperthermia apparatus for rewarming hypothermia victims would result in severe skin and outer tissue burns.